Casserole: Cut bread slices in half and lay on the bottom of a large baking dish (overlapping slices). In a large mixing bowl, beat eggs, pineapple, cinnamon, sugar and vanilla until well blended. Stir in milk and continue to beat until blended. Pour over bread making sure to coat well. Sprinkle with pecans, cover with foil and refrigerate for at least 4 hours. Preheat oven to 350 degrees, sprinkle evenly with cake mix and drizzle with butter. Bake uncovered for 20 minutes or until set. Syrup: To make syrup, place sugars and butter in heavy medium pot over medium heat. Stir well and lower heat. Cook until sugar is dissolved about 3 to 5 minutes. Stir in milk or water and continue to cook a few minutes longer. Pour over French toast Casserole.